The overall objective of the proposed work is the derivation and clinical application of more complete and accurate heart-lead transfer coefficients than are presently available and which account for tissue electrical properties and configuration of the chest. The specific objectives are those of (1) deriving and publishing two complete sets of transfer coefficients, one with a homogeneous torso and one with the same torso boundary and an inhomogeneous interior. (2) Analyzing the effects of inhomogeneities on various types of inverse solutions such as VCG lead systems and multiple-dipole heart equivalent generators. (3) Evaluating the influence of inhomogeneity effects by comparing ECG data from a fatally traumatized subject, with a model simulation utilizing the same individual's heart isochrone information. (4) Extending the model data by theoretical techniques to correct for body size and shape and (5) Optimizing electric, and combined lead systems for external defibrillation and pacing. These studies utilize an anisotropic, inhomogeneous, twice-life- size model of the human torso as a source of transfer coefficients, physical electromagnetic theory, and patient studies. The emphasis is on whole-body surface potential maps in order to maximize the amount of information available for interpretation.